Wave signaling system



June 1925- 1,539,821

E. H. ARMSTRONG WAVE S IGNALING SYSTEM Filed June 8-, 1923 (2M d wlb, ATTORNEYS Patented June 2, 192 5.

1,539,821; UNITED STATES PATENT OFFICE.

EDWIN HI ARMSTRONG, OF YONKERS, NEW YORK, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPO'RA TION OF PENNSYLVANIA.

WAVE SIGNALING SYSTEM.

Application filed June 8,

To all whom it may concern:

Be it known that I, EDWIN H. ARMSTRONG, residing at 1032 Warburton Avenue, Yonkers, in the county of Westchester, State of New York, have invented certain new and useful Improvements in Wave Signaling Systems; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as Will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to an electric regenerative system for amplifying varying electric currents, particularly radio or other high frequency signaling currents, wherein the varying potential of the current to be amplified is impressed on the system and the relation between the amount of re eneration and the degree of damping of the system is periodically varied to produce transient free oscillations proportional to the amplitude of the impressed potential and wherein the resulting free oscillations and this transient ordinarily unstable state to obtain super-regenerative amplification or action as described in my Patent 1,424,065 granted July 25, 1922, on a co-pending aprplication, Serial No. 480,563, filed June 2 1921. V

The invention has for its object the provision of a method and apparatus for improving the operation of vacuum valve super regenerative systems, particularly of the type in which the amount of regeneration, that is, the regenerative energy supplied to the system, (the so-called negative resistance) is varied, with respect to the degree of damping, that is, the rate of dissipation of the energy of the system.

I have discovered that the plate circuit of a vacuum valvein the signal'wave frequency regenerative circuit of a superregenerative system reacts lnductively to the auxiliary frequency at which the periodical variation in the relation between the amount of regeneration and the degree of damping of the system takes place. This reaction unless neutralized considerably afiects the response and generally lowers the stability of the system, resulting in the case of the reception and amplification of radio telephone signals, in poor quality of speech. To the end of overcoming this reaction and 1922. Serial No. 566,684.

in accordance with the invention, a tuning capaclty, preferably a variable condenser, is connected in the wave frequency regenerative circuit in' parallel with the vacuum valve. The condenser is adapted to be'so adjusted as to compensate for and neutralize the undesirable inductive reaction. The proper adjustment may be readil obtained by listening to the response'of t e system, the maximum response thereof indicating the proper tuning point.

The form of circuit arrangement illustrated in the drawings is the preferred embodiment of the invention. It possesses marked advantages in readily enabling the insertion of the proper value of capacity in the circuit to compensate for and neutralize the inductive reaction produced within the system by' the auxiliary fre uency. A more complete understanding of the invention may be had by reference to the drawings and the accompanying description. In these drawings: the system are continuously maintained n Fig. 1 illustrates diagrammatically a cir cuit arrangement adapted to operate in accordance with the invention; and Fig. 2 illustrates a more practical form of circuit arrangement in which a self oscillating vacuum valve is employed to supply the auxiliary frequency.

Referring now to Fig. 1, the source 1 of the incoming signaling or varying current to be amplified is associated with the tuned circuit 2, 3, containing the resistance 4, the circuit 2, 3being. connected in the grid circuit of the vacuum valve 5. The late circuit of the valve 5 contains the eed-back coil 6 which is associated with the inductance 2 thereby serving to control the amount of regeneration inthe wave frequency portionv of the'system. Y

The plate circuit of the valve 5, in accordance with the invention, is provided with a variable tuning condenser? by means of which the inductive reaction produced by the auxiliary frequency may be neutralized and compensated. In this case the auxiliary frequency .is produced by means of the 5 thereby periodically varying the amount of regeneration of the system with respect to the degree of damping thereof.

The plate circuit of the'valve 5 also 111- clud'es the telephones 10, the bypass condenser 11, the inductance 12, and the condenser and inductance 13 and 14 respectively, by means of which the auxiliary frequency may be controlled. The choke 15 serves to bypass the direct current of the battery 16 about the condenser 13.

The mode of o eration of this system is as follows: The a ternating current or electrical oscillations produced by the source 9 are impressed on the valve 8 so as to roduce in the tplate circuit thereof a varymg auxiliary requency current. which in turn is made eflective in the plate circuit of the valve 5 wherein'it serves to vary the amount of regeneration of the system. If

a continuous wave telephone signal arrives in the regenerative system, the wave or signal frequency currents will be amplified by super-regenerative action in groups corresponding in frequency to the local auxiliary frequency current and in amplitude. to the variations imposed by the speech. This complex wave is rectified by the valve 5 and transformed to two frequencies' 'in the plate circuit of the valve, one a frequency corresponding to the local modulating frequency and the other corresponding to the received voice or speech frequency.

While the maximum regenerative tendency in the wave frequency regenerative system exists when the voltage of the plate of the valve 5 is a maximum, nevertheless on account of the lag in building up the oscillations in the circuit 2, 3, 4, the maximum or peak values of the wave frequency current in this circuit lag behind the auxil iary frequency currents in the plate circuit of the valve 5. Hence, the rectified currents of the auxiliary frequency in the plate circuit of the valve 5 lag behind the electromotive force impressed across it.

Hence the valve of the system reacts inductively to the impressed electromotive force of the auxiliary frequency. It is this inductive reaction which is avoided and neutralized by the compensating tuning condenser 7.

In operation the system above described has an advantage of greatly increasing the response of the system, improving the .sta-

bility of operation thereof, and the quality of the speech when radio telephone signalsare received and amplified. The system also permits ready suppression of harmonies which might be created by overvarying'the potential of the plate circuit.

A more practical form of the invention is illustrated in Fig. 2. The wave frequency regenerative system of this arrange-.

ment, is similar to that of Fig. 1, and like reference numerals have been employed for similar portions of the system. In this fi ure, as in the case of F g. 1, the source 1 o the incoming signal is associated with the wave frequency regenerative amplifying system 2, 3, 4, 5, 6, 7 which is tuned to the 'wave frequency. In this arrangement, however, a self-oscillating valve system comprising a feed-back circuit including the valve 17 is arranged to vary the plate other energy collecting device and to re.

ceive wired wireless signals (so-called wire carrier current transmission) when associated with the conductor of such signals. It should also be understood that modifications may be made in the specific circuit connections above described without departing from the spirit and scope of the lhVGIllZlOIl.

I claim:

v1. The method of operating a superregenerative system having a certain degree of damping and which includes an oscillating system producing an auxiliary frequency for periodically varying the relation between the amount of regeneration and the damping of the system, which includes producing an inductive reaction within the system, and neutralizing and compensating for said reaction. I 2. An electric system adapted to produce super-regenerative action, including a wave frequency regenerative system having a certain degree of damping, means for periodically varying the relation between the amount of regeneration and the degree of damping of the system, comprising an oscillating system adapted to supply an auxiliary frequency to the regenerative system whereby an inductivereaction is produced in said system and means for neutralizing and compensating for said reaction.

3. An electric system adapted to produce super-regenerative action including a wave frequency "acuum valve regenerative sys-, tem. having acertain degree of damping,

means for periodically varying the relation between the amount of regeneration and the degree of damping of the system comprising a vacuum valve oscillating system adapttem and a compensating capacity in said regenerative system adapted to neutralize said reaction.

4. An electric regenerative system adapted to produce super-regenerative action, including a feed-back circuit havin a certain degree of damping, a vacuum va ve in said circuit, means for periodically varying the relation between the amount of feed-back and the degree of damping of the circuit comprising a self oscillating vacuum valve system adapted to supply an auxiliary frequency to said circuit whereby an inductive reaction is produced therein and a compensating variable capacity connected in parallel with said valve in the feed-back circuit adapted to neutralize said reaction.

In testimony whereof I aifix my signature.

EDWIN H. ARMSTRONG. 

